Emergency oil system

ABSTRACT

The present disclosure relates to lubricating oil systems, and more specifically emergency lubricating oil systems. This system continuously circulates oil through and/or from a reserve tank. This system does not utilize compressed air systems during normal operation to deliver lubricating oil. The system described herein does not utilize a piston to transfer lubricating oil from a reserve tank to engine elements.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, claims priority to and thebenefit of, PCT/US2014/042970 filed on Jun. 18, 2014 and entitled“EMERGENCY OIL SYSTEM,” which claims priority from U.S. ProvisionalApplication No. 61/867,833 filed on Aug. 20, 2013 and entitled“EMERGENCY OIL SYSTEM.” Both of the aforementioned applications areincorporated herein by reference in their entirety.

FIELD OF INVENTION

The present disclosure relates generally to lubrication systems. Moreparticularly, the present disclosure relates to an emergency lubricationsystem.

BACKGROUND OF THE INVENTION

Lubrication systems, such as those used in aircraft gas turbine engines,supply lubricant to bearings, gears and other engine components thatrequire lubrication. The lubricant, typically oil, cools the componentsand protects them from wear. A typical oil lubrication system includesconventional components such as an oil tank, pump, filter and oil supplyconduits.

If one of the lubrication system components fails malfunctions orsustains damage, the oils supply to the lubricated component may bedisrupted, resulting in potentially irreparable damage to the componentand undesirable corollary consequences. For example, if an engine oilpump fails or a supply conduit develops a severe leak, the resultingloss of oil pressure could disable the engine by causing overheatingand/or seizure of the bearings that support the engine rotor. Anaircraft engine that becomes disabled in flight is obviously a concern,especially for a single engine military aircraft operating in hostileairspace.

It is known to accommodate the possibility of a failure in the oilsystem by configuring the system so that it continues to supply oil tothe lubricated components for a limited time thereby enabling continuedtemporary operation of the engine. Such a system allows the aircraftcrew time to safely shut down the engine or to take other appropriateactions to safeguard the aircraft and its occupants. In a militaryaircraft, such a system can provide the crew with valuable additionaltime to return to friendly airspace.

SUMMARY OF THE INVENTION

According to various embodiments, a lubrication system is disclosed.This may be a lubrication oil system of an aircraft such as a helicopterand/or the lubrication of an engine system component and/or thehelicopter rotor assembly. A redundant lubricating system may include areserve lubricating oil tank coupled to a distal portion of alubricating oil main supply line, at least one supply line coupled tothe reserve lubricating oil tank, wherein the supply line couples thereserve lubricating oil tank to at least one engine component, such as abearing assembly. The reserve lubricating oil tank may be configured tocycle lubricating oil from the lubricating oil main supply line throughthe reserve lubricating oil tank to the supply line. The lubricating oilmay be provided to the engine components, during normal operation basedon an oil pressure of the lubricating oil main supply line. The systemmay include a check valve interposed between the reserve lubricating oiltank and a compressed air source. The system may include a lubricatingoil pressure sensor associated with the main supply line. Thelubricating oil pressure sensor may be configured to sense the oilpressure of the lubricating oil main supply line and/or a locationassociated with the lubricating oil main supply line. A check valve maypermit compressed air from a compressed air source to be delivered tothe reserve tank in response to the lubricating oil pressure sensorreading. A one way valve may be interposed between the reservelubricating oil tank and the lubricating oil main supply line.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1 illustrates a representative flow diagram of lubricating oil flowin response to normal operating conditions in accordance with variousembodiments;

FIG. 2 illustrates a representative flow diagram of lubricating oil flowin response to emergency conditions in accordance with variousembodiments; and

FIG. 3 illustrates a process for providing lubricating oil according tovarious embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration and their best mode. While these exemplary embodiments aredescribed in sufficient detail to enable those skilled in the art topractice the inventions, it should be understood that other embodimentsmay be realized and that logical, chemical, and mechanical changes maybe made without departing from the spirit and scope of the inventions.Thus, the detailed description herein is presented for purposes ofillustration only and not of limitation. For example, the steps recitedin any of the method or process descriptions may be executed in anyorder and are not necessarily limited to the order presented.Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Also, any reference to attached, fixed, connected,or the like may include permanent, removable, temporary, partial, full,and/or any other possible attachment option. Additionally, any referenceto without contact (or similar phrases) may also include reduced contactor minimal contact.

According to various embodiments and with reference to FIG. 1, arepresentative lubricating oil main supply line 115 is depicted. Thisoil main supply line 115 may be for a vehicle, such as an aircraft. Forinstance, main supply line 115 may supply lubricating oil to ahelicopter engine or aircraft engine. Oil supply line 115 delivers oilto elements of a gas turbine engine, such as bearings assembliesgenerally designated as 1 and 3, and to a reserve tank 120. Bearingassemblies, in general, reduce friction between a rotating engineelement and stationary engine components. Oil pump 130, driven by theengine (not shown), pumps oil from a sump/oil supply reservoir 125through main oil supply line 115 to effect lubrication of the enginesystem components of the gas turbine engine (e.g. bearings assemblies 1,3 and roller bearing 10, and/or the like).

Reserve tank 120 may be empty (and/or less than full) of oil on enginestart-up. Reserve tank 120 may be located towards and/or at the distalend of the path of lubricating oil main supply line 115. As lubricatingoil is delivered through main supply line 115 under pressure, reservetank 120 may gradually fill with lubricating oil. Stated another way, aslubricating oil is delivered through main supply line 115 underpressure, the amount of lubricating oil in reserve tank 120 tends toincrease. This filling of reserve tank 120 may occur in concert withlubricating oil being delivered to bearings assemblies 1, 3. As reservetank 120 fills and pressure within reserve tank 120 increases, oil maybe delivered from reserve tank 120 through supply lines 135 and 145 tobearings assemblies 1, 3 respectively. This delivery circulates thelubricating oil from reserve tank 120. Thus, lubricating oil is nottrapped in reserve tank 120 until needed. Reserve oil is consistentlybeing circulated via supply lines 135 and 145. Stated another way, thissystem continuously circulates oil through and from a reserve tank.“Continuously” in this context may refer exchanging/cycling lubricatingoil in the reserve tank 120 without trapping the lubricating oil in thereserve tank 120 for an extended period of time. Trapping oil in areserve tank may degrade the quality of the oil, lead to build up inlines, and may be otherwise undesirable. Additionally, no additionalforce application, such as through compressed air or additional pump isused to circulate oil from reserve tank 120 during normal operatingconditions. Normal operating conditions as used herein may be when mainsupply line 115 comprises adequate oil pressure to deliver lubricatingoil to the system. During normal operating conditions, an air checkvalue 150 coupled to a compressed air supply 155 may be in a closedposition and/or restrict compressed air in the compressed air supply 155from entering the reserve tank 120. A valve, such as a one-way valve160, may be located between a distal end of main supply line 115 andreserve lubricating oil tank 120, such that lubricating oil delivered bymain supply line 115 may not exit reserve tank 120 via main supply line115. A sensor, such as oil pressure sensor 170, may be located alongand/or coupled to main supply line 115 to measure and/or determine thatthe oil pressure in main supply line 115 is above a predetermined normaloperation oil pressure threshold.

In the event that the main lubricating oil supply line 115, pump 130 orother elements of the normal lubricating system should be damaged orfail for any reason, the various bearings, such as bearing assemblies 1,3 of the engine would be starved for oil and catastrophic failure of theengine may occur. This is undesirable.

Integrated emergency lubrication system, generally designated as system200 in FIG. 2, is designed to cope with such a situation and sustainsubstantially uninterrupted and/or uninterrupted lubrication of bearingassemblies 1, 3 and continued safe operation of the engine for apredetermined amount of operational time and at a predetermined rate ofpower. This may occur during emergency oil conditions (e.g. in responseto the oil pressure of main supply line 115 dropping below the normaloperation oil pressure threshold). The predetermined amount of time maybe any suitable amount of time. According to various embodiments, thepredetermined amount of time is between about 15 and 180 seconds,between about 4 and 8 minutes, and between about 1 and 9 minutes. Invarious embodiments, the predetermined amount of operational time foruninterrupted lubrication of emergency oil during emergency conditionsis six minutes. The predetermined rate of power may be any suitable rateof power. According to various embodiments, the predetermined rate ofpower is between about 50-90% normal operational power, between about60-85% normal operational power, and between about 70-80% normaloperational power. According to various embodiments, the predeterminedrate of power is full normal operational power and/or between about60-100% normal operational power. In various embodiments, thepredetermined rate of power is about 75% normal operational power.During that time, (e.g. emergency oil conditions), the engine's operatorcan reduce power to the engine and take other appropriate emergencymeasures.

According to various embodiments and with reference to FIG. 2, based ona measured loss of oil pressure in main lubricating oil supply line 115,such as via a detection by sensor 170, check valve 150 may open. Thus,compressed air from compressed air supply 155 may be delivered viacompressed air supply line 180 to reserve tank 120. FIG. 2 depicts lossof lubricating oil flow through main lubricating oil supply line 115.This loss of lubricating oil delivery is depicted by an “X” over thelubricating oil paths from main supply line 115 to bearings assemblies 1and 3, roller bearing 10 and through lubricating oil supply line 115itself. The loss of one or more path of lubricating oil delivery may beassociated with an emergency oil condition. During loss of lubricatingoil delivery, oil is not supplied to bearings assemblies 1 and 3, rollerbearing 10 and/or a decreased amount of oil is being supplied tobearings assemblies 1 and 3, roller bearing 10 via the main oil supplyline.

Compressed air from compressed air supply 155 may provide theforce/pressure to deliver lubricating oil in reserve tank 120 toelements of engine, such as bearings assemblies 1 and 3. According tovarious embodiments, the pressure of the lubricating oil supplied isless than about 60 pound-force per square inch gauge (PSIG) (4.136854368bar). In this way, buffer air may pressurize the reserve tank 120. Inresponse to reaching an emergency oil operational pressure level,lubricating oil may be delivered through supply lines 135 and 145 tobearing assemblies 1 and 3. In emergency oil conditions, lubricating oilmay be delivered from reserve tank 120 to bearing assemblies 1 and 3 ina jet or mist. Thus, compressed air and/or buffer air may be used duringemergency conditions but jet and/or mist delivery is not intended forlong term use in normal operating conditions. Stated another way,compressed air is not used to deliver lubricating oil from the reservetank 120 during normal operating conditions. In this way, inefficientuse of compressed/buffer air is reduced. Moreover, in this embodiment, apiston is not utilized to deliver emergency oil to various enginecomponents.

The size of the reserve tank 120 may affect the length of timelubricating oil is applied to engine elements during an emergency oilcondition. Reserve tank 120 may be sized to accommodate any desiredlength of time to provide lubricating oil during emergency conditions.Lubricating oil may be delivered to bearing assemblies 1 and 3substantially simultaneously. For instance, a single port in reservetank 120 may split and form an inlet to each supply line 135 and supplyline 145. According to various embodiments, supply line 135 and supplyline 145 may be individually coupled to reserve tank 120, such as by twodistinct couplings. The volume of reserve tank 120 and/or desired rateof flow may determine the pressure of the compressed air supplied. Also,the gauge and length of travel of supply line 135 and/or supply line 145may determine the pressure of the compressed air supplied. The pressureof the air supplied may be any desired pressure. According to variousembodiments, the pressure of the compressed air is about 50 pounds persquare inch (about 3.447×10⁵ N/m²) absolute (PSIA) air. This pressuremay be selected based on the length of time and volume of lubricatingoil desired to be delivered to engine elements. Similarly, thediameter/gauge and/length of supply lines 135 and 145 may be sized toaccommodate a desired pressure, length of time to deliver oil, and/orrate of power. Determining a rate of compressed air delivered by thecompressed air source 155 may be based on at least one of a length ofthe supply line 135, 145, a gauge of a portion of the supply line 135,145, a nozzle selected for the distal end of the supply line, and/or avolume of the reserve tank 120. Moreover, a distal nozzle of supplylines 135 and 145 feeding lubricating oil to engine elements, such asbearing assemblies 1 and 3, may be sized to accommodate a desiredpressure, length of time to deliver oil, and/or rate of power.

In response to oil pressure in main oil supply line 115 being restoredto normal operating conditions (over the normal operating conditionthreshold), reserve tank 120 may be refilled and the emergency oilsystem may be ready for utilization in an emergency condition. Forinstance, in response to normal operating conditions being restored,sensor 170 may detect normal oil pressure from oil supply 125. Inresponse, sensor 170 may trigger check valve 150 to close and compressedair may be discontinued from being provided to reserve tank 120. Oilwill continue to circulate through the system and through reserve tank120, without additional force provided by the pressure accumulatedthrough compressed air source 155. The system described herein maymaintain operation for at least 30 minutes once main oil supply has beenrestored.

According to various embodiments and with reference to FIG. 3, a methodof managing oil supply is described. Oil is delivered through mainsupply line 115 under pressure to engine components, such as bearingassemblies 1 and 3 (Step 310). As reserve tank 120 is located at thedistal end of main supply line 115, the volume of lubricating oil inreserve tank 120 increases in response to lubricating oil beingintroduced to/through main supply line 115 (Step 320). Reserve tank 120may be empty or partially full on startup. Lubricating oil is deliveredthrough supply lines 135 and 145 to engine components based on oilpressure of reserve tank 120 (Step 330). The oil pressure is measured ata location, such as in main supply line 115, engine elements, and/ordelivery tracks from main supply line 115 (Step 340). A determination ismade that oil pressure at a measurement location is at least one of morethan or less than a threshold (Step 350). In response to the oilpressure is more than the threshold normal operations continue (Step353). In response to the oil pressure of main supply line and/or at ameasurement location being less than a normal operation threshold,compressed air is provided to reserve tank 120 from a compressed airsource 155 through check valve 150 (Step 355, 360). Oil Pressure inreserve tank 120 increases (Step 370). The rate of flow of lubricationoil delivered through supply lines 135, 145 increases based on the oilpressure increase of reserve tank 120 (Step 380). Measurements arecontinued to determine if normal operating conditions are restored.

Benefits, other advantages, and solutions to problems have beendescribed herein with regard to specific embodiments. Furthermore, theconnecting lines shown in the various figures contained herein areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. It should be noted that manyalternative or additional functional relationships or physicalconnections may be present in a practical system. However, the benefits,advantages, solutions to problems, and any elements that may cause anybenefit, advantage, or solution to occur or become more pronounced arenot to be construed as critical, required, or essential features orelements of the inventions. The scope of the inventions is accordinglyto be limited by nothing other than the appended claims, in whichreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.”Moreover, where a phrase similar to “at least one of A, B, or C” is usedin the claims, it is intended that the phrase be interpreted to meanthat A alone may be present in an embodiment, B alone may be present inan embodiment, C alone may be present in an embodiment, or that anycombination of the elements A, B and C may be present in a singleembodiment; for example, A and B, A and C, B and C, or A and B and C.Different cross-hatching is used throughout the figures to denotedifferent parts but not necessarily to denote the same or differentmaterials.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “one embodiment”, “an embodiment”,“various embodiments”, etc., indicate that the embodiment described mayinclude a particular feature, structure, or characteristic, but everyembodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed. After reading the description, it will be apparent to oneskilled in the relevant art(s) how to implement the disclosure inalternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. Different cross-hatching may be used throughout the figuresto denote different parts but not necessarily to denote the same ordifferent materials. No claim element herein is to be construed underthe provisions of 35 U.S.C. 112, sixth paragraph, unless the element isexpressly recited using the phrase “means for.” As used herein, theterms “comprises”, “comprising”, or any other variation thereof, areintended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises a list of elements does notinclude only those elements but may include other elements not expresslylisted or inherent to such process, method, article, or apparatus.

What is claimed is:
 1. A redundant lubricating system comprising: areserve lubricating oil tank coupled to distal portion of a lubricatingoil main supply line; a one way valve interposed between the reservelubricating oil tank and the lubricating oil main supply line, whereinlubricating oil delivered to the reserve lubricating oil tank by thelubricating oil main supply line may not exit reserve tank via thelubricating oil main supply line; a supply line coupled to the reservelubricating oil tank, wherein the supply line couples the reservelubricating oil tank to at least one engine system component, whereinthe reserve lubricating oil tank is configured to continuously cyclelubricating oil from the lubricating oil main supply line through thereserve lubricating oil tank to the supply line based on an oil pressureof the lubricating oil main supply line; and a check valve interposedbetween the reserve lubricating oil tank and a compressed air source. 2.The redundant lubricating system of claim 1, further comprising alubricating oil pressure sensor.
 3. The redundant lubricating system ofclaim 2, wherein the lubricating oil pressure sensor is configured tosense the oil pressure of the lubricating oil main supply line.
 4. Theredundant lubricating system of claim 3, wherein the check valve togglesfrom a closed orientation to an open orientation in response to thelubricating oil pressure sensor reading.
 5. The redundant lubricatingsystem of claim 1, wherein the redundant lubricating system isconfigured to deliver lubricating oil to the at least one engine systemcomponent during emergency conditions for at least 6 minutes.
 6. Theredundant lubricating system of claim 1, wherein the redundantlubricating system is configured to deliver lubricating oil to the atleast one engine system component during emergency conditions for atleast 30 seconds.
 7. The redundant lubricating system of claim 1,wherein the redundant lubricating system is configured to deliverlubricating oil to the at least one engine bearing assembly at about 75%of normal operational power.
 8. The redundant lubricating system ofclaim 1, wherein the redundant lubricating system is configured todeliver lubricating oil to the at least one engine system component atbetween about 65% and 100% of normal operational power.
 9. The redundantlubricating system of claim 1, wherein the supply line comprises morethan one supply line to more than one engine bearing assembly.
 10. Theredundant lubricating system of claim 1, wherein compressed air from thecompressed air source is configured to increase oil pressure of thereserve tank, wherein an increased oil pressure in the reserve tankincreases a flow rate of lubricating oil from the reserve tank to the atleast one engine system component.
 11. The redundant lubricating systemof claim 1, wherein the redundant lubricating system is configured toincrease an amount of lubricating oil in the reserve tank in response tothe oil pressure in the lubricating oil main supply line being restoredto an operational level.
 12. The redundant lubricating system of claim11, wherein the system is configured to maintain operation for at least30 minutes in response to the oil pressure in the lubricating oil mainsupply line being restored to the operational level.
 13. The redundantlubricating system of claim 1, wherein the system configured for use ina helicopter rotor assembly.
 14. A method comprising: increasing avolume of oil in a reserve tank delivered from a lubricating oil mainsupply line, wherein a one way valve is interposed between the reservelubricating oil tank and the lubricating oil main supply line, whereinlubricating oil delivered to the reserve lubricating oil tank by thelubricating oil main supply line may not exit reserve tank via thelubricating oil main supply line; sensing an oil pressure associatedwith the lubricating oil main supply line by a sensor; toggling aposition of a check valve interposed between a compressed air source andthe reserve tank in response to the sensed oil pressure in a mainlubricating oil supply line being below a predetermined threshold;increasing an oil pressure in the reserve tank in response to deliveringcompressed air to the reserve tank; and providing by the reserve tanklubricating oil via a supply line to at least engine system componentlubricating oil based on an increased oil pressure in the reserve tank,wherein the reserve tank is configured to continuously cycle lubricatingoil from the lubricating oil main supply line through the reservelubricating oil tank to the supply line based on the oil pressure of thereserve tank.
 15. The method of claim 14, further comprising determininga rate of compressed air delivered by the compressed air source based onat least one of a length of the supply line, a gauge of a portion of thesupply line, a nozzle of the supply line, and a volume of the reservetank.
 16. The method of claim 14, further comprising determining a rateof compressed air delivered by the compressed air source based on apredetermined rate of flow to the at least one engine system component.17. The method of claim 14, wherein lubricating oil is provided to theat least one engine system component at between about 65% and 100% ofnormal operational power.
 18. The method of claim 14, whereinlubricating oil is provided to the at least one engine system componentduring emergency conditions for at least 6 minutes.